A: Yes, those pond heaters are expensive to run! But guess what? You don’t need one in the first place!

Heaters are more frequently used in aquariums, particularly those that house warm-water fish like tetras, danios or angelfish.

In your pond, the fish will overwinter just fine without a heater—even if temperatures drop below freezing. Pond fishes like koi and goldfish naturally go into wintertime hibernation when temperatures fall. They’ll stop eating, their metabolisms will slow way down and they’ll snooze through the winter without worrying about how warm their water is.

However, if you live in areas that experience freezing temperatures that cause your pond to ice over, you do need to worry about keeping a hole in the ice. The hole allows toxic gases like ammonia to escape while allowing oxygen in, and your fish will need that fresh O2.

So how do you create that hole? Not with a pond heater! Check out these much cheaper alternatives:

De-Icer: A de-icer floats on the water surface and melts a hole in the ice. Unlike a heater that actually warms the entire pond, a de-icer simply melts an opening in the ice sheet, thereby allowing for gas exchange.

Aerator: Rather than create a hole in the ice from above, an aerator like the PondAir™ (for smaller ponds) or KoiAir™ (for larger ponds) circulates the water below the ice sheet. In areas with mild winters, that subsurface water movement will keep a hole in the ice—but when temps really dip, an aerator may not be enough to maintain a vent hole.

De-Icer, Aerator Combo: An excellent and convenient option to consider is the PondAir™ & Thermo-Pond Combo. It combines both the Thermo-Pond de-icer and PondAir™ Aeration Kit, providing your water feature the one-two punch it needs to stay well-vented throughout the winter. Watch the video below for benefits and installation.

If you live in an area with temperatures that hover around the freezing mark, consider picking up a Thermo Cube®. It’s a thermostatically controlled outlet that turns on when air temperatures drop below 35°F and turns off when air temps rise above 45°F.

So put that pond heater on Craigslist and invest in a de-icer, aerator and thermostatically controlled outlet. It’ll save you money in the long run!

Pond Talk: What method do you use to keep a hole in the ice in your pond?

Q: I was out at my pond today and it is still partially covered with ice. I have a de-icer and aeration – isn’t that enough to keep the ice off my pond?

Mark – Buffalo, NY

A: During these frigid months of the year, a hole in the ice means the difference between life and death for your pond fish. That opening allows oxygen to flow into the liquid water while it dissipates harmful gases caused by decaying debris and fish waste into the air.

Bubblers and de-icers both keep a hole open in the ice, but they go about it differently.

Bubblers, like the ones found in Airmax® PondAir™ Aeration Kits, are designed to gently and quietly move the water surface, and that action keeps a hole open in the ice. The aerator also delivers oxygen to the lower levels in your pond while bringing harmful gases to the surface to be released.

De-icers, such as the Thermo-Pond De-icer, melt surface-forming ice and create a gas exchange vent in the ice. While effective, during cold windy nights they may not be be enough to keep a hole open on their own.

Bubbler-De-icer Combos, like Airmax® PondAir™/Thermo-Pond De-icer Combo, is an energy-efficient option. Because the aerator will bring harmful gases to the surface and your de-icer helps to keep the hole melted, you’ll be sure to keep the ice vent open.

The bubblers, de-icers and combos are not designed to warm the water or keep the entire pond surface ice free. They’re meant to keep an opening for gas exchange, which is all that’s needed for the fish in your pond.

As long as the equipment you have in the pond is sized correctly (see your manual for details on what yours can effectively handle), you won’t need a larger hole. Your fish are less active, not eating and producing less waste, and so they won’t have the gas exchange requirements they do in the warmer months.

If your vent does freeze over during extra cold temperatures, simply pour hot water on the ice where the hole once was. It’ll melt the hole back open – and your fish can breathe a sigh of relief!

A: With winter officially starting in just one week, the cold weather is settling in across the country. Since your fish don’t have miniature submerged Koi calendars to check, what is it that tells your fish it is time to hibernate?

Koi are cold-blooded creatures, which means their body temperatures and activity levels are directly correlated with the ambient temperature. Koi are active and alert when their environment is warm and will start to slow down as the water temperature decreases. Once the water temperatures start to dip below 46°F your fish tend to stop eating and will retreat to the bottom of the pond. Your fish use the decrease in temperature along with the shortening day lengths as a trigger to prepare for winter.

As the water begins to cool, your fish will become less active as their bodily functions slow down. Less activity means a slower digestive process, less demand for food. It is this decrease in food digestion that warrants the use of wheat germ based foods like Pond Logic® Spring & Fall Fish Food. These types of food are easier to digest that regular food reducing the risk of leaving undigested food to rot inside a dormant fish, which can potentially be fatal.

As the temperatures continue to decline towards 40°F, the blood flow and respiratory rate of the fish will drop to an extremely low rate where their body is hardly functioning. You may hear people say that your Koi are sleeping in the winter and while fish do sleep this goes way beyond the standard drop in bodily functions associated with some much needed shut-eye. This extreme internal slow down ensure survival with even the most limited resources with cases of dormant fish lasting 150 days without food.

The whole over-wintering scenario sounds a little extreme to us but it is truly a natural and normal process for your fish. They do not require much attention in the winter but there are a few things you can do to ensure their winter break is a success. When a layer of ice begins to form over the pond, maintain an opening for gas exchange using an aeration kit or pond de-icer, like the PondAir™ & Thermo-Pond Combo.

Pond Talk: What do you do to help your fish through the winter season?

Q: If I run my waterfall pump for a few hours a day during winter, will my fish be OK?

Lenny – Waggoner, IL

A: While it may be beautiful to run your waterfall during winter, it is not always recommended. A waterfall pump moves and circulates oxygenated water through the water column, but if you run it for just a few hours each day, your fish – and your pocketbook – may suffer. Here’s why.

Oxygen Starved: First of all, your fish need plenty of fresh oxygen, even when they’re semi-dormant in the wintertime. A few hours of circulation from a waterfall pump won’t keep a hole in the ice or infuse enough oxygen into the water, so the lack of fresh air will stress out your finned pals and put them at risk for disease.

Ice Dams: If you run your waterfall pump in northern climates during near- or sub-freezing temperatures, ice dams can develop and grow in size, diverting water from the pond. For this reason, you’d need to keep an eye on your water level – particularly if you have a longer stream. When the water level gets too low, your pump could become damaged, which means you’ll need to fork out some cash to replace it.

Overstressed Pump: Speaking of replacing a pump, take a look at your pump’s manual. Does it say that your pump is it designed for use in freezing temperatures? Generally speaking, pumps should be at least 2,000 GPH to operate in the winter.

Big Energy Bill: The cost of running a waterfall pump can easily top $100 a month. The cost of running a de-icer alone to keep a hole in the ice for gas exchange can cost up to $75 a month. Those aren’t cheap options! An aerator; however, is a cost-effective solution that’ll only cost you around $1.70 a month. In addition, you can use aerators throughout the year.

Because of the risk of damaging the waterfall pump and not providing enough oxygen to your fish – along with the high cost of running it all the time – we recommend removing the pump this winter and replacing it with an aerator.

Stowing the Pump

When you remove your pump, submerge it in a 5-gallon bucket of water to keep all its seals lubricated and store it indoors in a place that won’t freeze. Blow out the water and debris in your tubing with an air compressor and cap it off. Drain the skimmer boxes below the weir door. And spray your filter media off with a hose, pump out any water in the filter box and give it a good scrubbing.

Installing Aeration

Once your pump is removed and stored for the season, install an aeration system that’s sized right for your pond. KoiAir™ Aeration Kits, are designed for ponds up to four feet deep and 16,000 gallons, includes a compressor, airline and a diffuser plate. PondAir™ Aeration Kits are suited for ponds up to two feet deep and 2,000 gallons, includes a compressor, airline, check valves and air stones. Simply connect the diffuser plate or air stones to the compressor, submerge the plate/stones and plug it in, and you’re good to go!

You’ll be delivering oxygen to your fish, keeping a hole in the ice and preserving your waterfall pump – and saving a bunch of your hard-earned money.

Q: My fish hang out near my waterfall during hot days. Do I have enough aeration in my pond?

Amanda – Rowlett, TX

A: On hot days, who wouldn’t want to hang out near a waterfall! For humans, the water pouring into the pond cools and hydrates the air; for fish, that action acts as a giant aeration system, infusing oxygen into the water beneath the waterfall.

But that raises a valid question: If your fish spend a lot of time near the waterfall, does it mean they’re not getting enough oxygen? Yes, it’s possible. Here are some questions to ask yourself about your pond’s aeration situation.

Is It Getting Full Aeration?

If you’re running your waterfall 24 hours a day, your pond is likely getting full aeration. If your pond is more than 24 inches deep, however, and you have a skimmer/waterfall system in place, more aeration may be necessary. Why? Because the oxygenated water will circulate across the water surface, leaving the water at the bottom of the pond stagnant. Adding an aeration system will prevent stagnation by raising the bottom water to the surface.

Do You Have Many Plants?

Plants may release subsurface oxygen to the water during the day, but at night those plants take in oxygen, which means your fish may be gasping for air. If you have quite a few plants and your waterfall is off—and you experience an algae bloom—you should definitely think about adding some aeration.

Do You Have Many Fish?

The more fish in your pond, the more oxygen you’ll need—which means you’ll need more aeration. If your pond has a high fish population, consider adding some more aeration. For comparison, we recommend one 6- to 8-inch fish per 10 square feet of surface area.

How’s Your Muck Level?

Another clue that your pond is insufficiently aerated is the amount of muck that has accumulated at the bottom of your pond. When your pond is properly aerated, muck naturally breaks up thanks to the healthy and growing population of gunk-gobbling beneficial bacteria.

Low-Cost Aeration

If any of these scenarios apply to your pond, we recommend adding the energy-efficient Airmax® PondAir™ Aeration System for ponds up to 2,000 gallons or the Airmax® KoiAir™ Aeration System for ponds up to 16,000 gallons. They help to circulate the water and add valuable oxygen, providing the best possible environment for your fish.

Pond Talk: What do you do to ensure your finned friends get enough oxygen during the summer months?

A: They say a tiger can’t change its stripes – but did you know a koi can change its colors?

As you get to know each one of your koi personally (and you will if you haven’t already!), you may notice changes in the pigment, color depth and hue in the fish’s black, white and red scales. Don’t worry: It’s not necessarily a cause for panic. The color changes can be caused by several factors, including:

Sun Exposure: During the summer when the sun is shining, you get a tan; during the winter, you don’t. It’s the same thing with koi. Their scales can change color depending on their exposure to that bright orb in the sky. They won’t turn an Oompa-Loompa orange during the summer (though that may not be a bad thing to some koi keepers!), but you may notice a color change in some of your fish after their winter slumber.

Genetics: Koi experts will tell you how critical a role genetics plays in the coloration and patterning of koi. Dominant and recessive genes dictate how much hi (red), sumi (black), shiroji (white) and other colored markings appear. And, just like your hair color can change based on your genetic makeup, the koi’s scale color can change, too.

Stress: If your fish are stressed, they may show their unhealthiness in their coloring – just like when you take on a pallor-type tone when you’re under the weather. Make sure to keep your pond clean and well-oxygenated with an aeration system, like the Airmax® KoiAir™ Water Garden Aeration System. Also be sure to check your water quality with a water test kit, like the API® Pond Master Test Kit that measures ammonia and pH, and correct it if necessary.

Diet: A koi’s overall health – just like human’s – is affected by what it eats. Feed your fish food that has enough vitamins and nutrients to support vibrant color, like Pond Logic’s Growth and Color Fish Food. It contains top-quality ingredients, vitamins, natural color intensifiers and chelated minerals that enhance colors in koi and goldfish. To punch up your koi’s colors even more, add some oranges and watermelon to its diet.

What if my pond has aeration and it still freezes over? Will my fish be okay?
Sue – Boston, MA

The reasons for aeration during the winter months are largely the same as they are during warmer weather. The oxygen provided by aeration is vital to the health of fish – all year ‘round. In the winter, aeration does double duty, both by introducing sufficient oxygen to the water, and by preventing the formation of ice that could contain harmful gases produced by leaves and other decaying material on the pond’s bottom. As long as the aerators keep some of the water from freezing, the fish in the pond will have sufficient oxygen to weather the cold.

If your aerator can’t keep up with the impact of a long cold snap, and the pond freezes entirely for a short time, your fish should be fine. Short term freezes shouldn’t pose a threat to a well maintained pond – and fish will have sufficient oxygen to survive the temporary freeze. During longer cold snaps, however, harmful gases can accumulate, and you may need to take measures to open the ice. To accomplish that task, it’s important to avoid the use of hammers, drills or other percussive tools. The effects of violent vibration can be harmful to fish. Instead, try applying buckets of hot water to melt vent holes.

To prevent freezing, we recommend the use of our Airmax® Aeration Systems. With the system installed, it’s wise to prepare for winter by situating stones throughout the pond. For an added measure of assurance, you may also want to suspend some stones closer to the surface to generate more surface-level water movement, while leaving the bottom of the pond still for fish.

Pond Talk: Have you had your pond freeze over even with the help of an aerator?